Rheostat.



T. RHODUS'.

RHEOSTAT.

APPLICATION FILED MAY 10, 1912. 1,053,21 9. Patented Feb. 18, 19121.

2 SHEETS -SHBE.T 1.

T. RHODUS.

- RHEOSTAT.

APPLICATION FILED MAY 10, 1912.

Patented Feb. 18,1913.

2 SHEETS-SHEET 2.

THOMAS BHODUS, OF CPIIQAGO, ILLINOIS.

R HEOSTA'I.

Speciflcatioaof Letters Patent.

Patented Feb. 18, 1913.

'Application filed May 10, 1912. Serial No. 696,330.

- To all whom 2'25 may concern: I

Be it known that I, THOMAS RHoDUs, a citizen of the United States of America, and a resident of Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Rheostats, of which the following is a specification.

This invention relates to that class of rheostats in which a series of spiral windelements.

ings or convolutionsof wire wound upon a suitable insulating core or support, and circularly disposed, constitutes the station ary electrical resistance element of the apparatus, and is' electrically engaged by a movable element orcontact which is shiftable in a circular path corresponding with the circular disposition of said stationary resistanceelement to increase or diminish the amount of electrical resistance in the circuit. And the present improvement has for -its objectlto provide'a simple and durable struc-' tural formation and arrangement of parts whereby an extended and eflicient surface contact between the stationary resistance and the movable contact element is attained with an avoidance of friction and wear between the same.

A further object is to provide an economifoal and compact structural arrangement and combination of the rheostat parts adapt-' ed to afford ease in operation, efiicient'elec;

trical contact with .a minimum degree of friction and wear, and ample ventilation to dissipate the heat generated in the resistance element, all as will hereinafter more fully- I and 10 are coacting outer and inner blocks appear. j

In the accompanying drawings, Figure 1, 1

is a central sectional elevation of the present apparatus, taken on line w-'w of Fig. 3. Fig. 2, is a detail perspective view showing the engaging end of the operating shaft, the actuating stem and coupling sleeve, in detached relation. Fig. 3, is a front eleva-' 'tion, with parts of the inclosing casing-in section 01111116 a: '-a:", Fig. 1. Fig. 4;, is an enlarged detail sectional elevatlon on line :v a; Fig. 3, of the resistance and contact Similar reference numerals indicate like parts in the several views.

Referring 'to th drawings, 1 -represents the usual carrying plate or board upon which the rheostat is mounted in connection with other usual recording and indicating apparatus, and. said plate or board may have the usual vertical or horizontal arrangements as required in the varied uses of the apparatus.

2 is a supporting spider having a 'plurality of'angularly, disposed feet 3 by which it is attached to the plate or board 1, and

with a series of circularly disposed lugs 4' formed with suitably arranged orifices or reticulations to provide ventilating passages for the atmosphere, to dissipate the heat generated by the resistance element in actual and continued use.

7 1s a longitudinal bar of insulating material, disposed diametrically of the supporting spider 2, secured to theouter face thereof as shown, and adapted to support in.

proper insulated relation the active elements of the rheostat.

8 is a pair; of binding posts arranged at oneend of the bar 7 and adapted for the attachment of the line wires of the circuit, and

with the resistance element and the movable contact member thereof.

9 1s a supporting bracket attached to the plate 7, and adapted in turn to support theresistance element hereinafter described,

of insulating material, also carried by the bar 7 and adapted to maintain said resistance element in proper relation to the other parts of the apparatus.

having connections as hereinafter described 11 is a bearing bracket or hub secured.

centrally to the bar 7 aforesaid, and adapted to provide a bearing and support for the axially arranged operating shaft of the apparatus.

The resistance element above referred to, is circular in form, arranged concentric with the axis of the spider 2 aforesaid, and comprises the usual open band ring or core 12 ofmetal or other suitable material, the respective ends of which are made to overlap and are secured to the aforesaid supporting bracket 9, by ,an attaching bolt 13, as shown in Figs. 1 and 3. Inclosing said ring or core 12, with the exception of its attaching ends afdresaid, is a sheath 14 of insulating material, upon which the windings or convolutions, of resistance ,wire15 areiwound 1n the ,usual spiral manner, and as usual in the present type of rheostats one end of the .5 resistance wire 15 is preferably left unconnected electrically, while the other end is 1 electrically connected by an intermediate conductor 16 with one of the terminal or, blnding-posts 81 of the apparatus, as illus-v trated in Figs. 1 and 3. I

17 is the axially arranged operating shaft of theapparatus, journaled in any suitable manner in the bearing bracket or hub 11 aforesaid, with its outerend extending out through an enlarged central orifice in the head 6 of the inclosing shell or casing, for the attachment of an operating arm or crank 18, when it is desired tomanipulate the apparatus from the front, and as illustrated in i 20 dotted lines in Fig. 1. The inner end of said the electric circuit.

' 21is a carrying arm or rod formed at its inner end with an angularly disposed cylinr drical extension 22 by which it is journaled in a transverse orifice in the operating shaft 17 aforesaid. 9

23 is a grooved contact sheave journaled 40 on the outer end of the carrying rod or arm j 21 and adapted to have rolling contact upon the edge ofthe convolutions or windings of the resistancewire 15 before described. A

material feature of the'present inventioncomprises the formation of the groove inthejcontact sheave of -a V shape as shown, in that it cooperates with the rounded edges of the flattened ovaliform windings of the wire 15. to afford a very extended electrical contact, without, friction or tendency to bottomj after ordinary wean. In the pres- "ent construction it is preferable to bend the outer end of the carrying arm or red 21, so that its outer sheave carrying portion will be radial 'to'the axis of the operating shaft 17, and in order that the groove of the sheave 23'will travel'in a true concentric path.

and at its other end tothe carrying arm or rod 21, with a normal tendency to force the 1 v8116,1378 23 i t nt' ct with'the resistance Y a Y supporting spider having a plurality of cir;

Wire-1'5 aforesaid. a

v x is an actuating stem or rod p'rovided- 24 is an obliquely disposed coilspring at 60 tached' atone end to the operating shaft 17,

with anoperating handleor' wheel 26, on .1ts rear end. Said stem or rod is disposed in longitudinal alinement and adapted for operative engagement with the operating. shaft 17 aforesaid.

. 27 is a coupling sleeve formed of insulating material, secured to the forward end of vthe actuatingstem and projecting therefrom to provide a receiving socket-for the so desired the stem 25 and sleeve 27 may be integrally formed of'insulating material.

Having thus fully described my said ininsulated from the operating shaft. When vention what-I claim as new and desire to secure by Letters Patent, is v 1. In a rheostat, the combination of a resistance wire formed into a series of convolutions, and a revoluble contact member formed with a-peripheral groove the walls of which groove bear upon-the surface of the convolutions at opposite sides .of the transverse axes of the same.

2. In a rheostat, the combination of a resistance wire formed into a series of convolutions of a flattened ovaliform, and a. revoluble contact member formed with a peripheral groove the walls of which have bearing on an edge ofsaid convolutions.

3. In a rheostat, the combination of a resistance'wire formed into a series of convolutions of a flattened ovaliform, and a revoluble contact member formed with a peripheral groove the walls of which arcinclined toward each other and have bearing onan edge of the said convolutions.

4. In a rheostat, the combination of aresistance wireformed into a series of convolutions and a revoluble contact member formed with a V shape' peripheral groove the walls of which have bearing on the outer surface of said convolutions.

' 5. In a rheostat, the combination of a supporting spider having a plurality. of circularly disposed lugs a reticulated inclosing shell attachedto said; lugs, a longitudinal bar of insulating material secured'to said spider, a ring shaped resistance element, movable contact memberiand-e'lectrical cons nections mounted on said bar, the movable contact member-comprising in part a'centrally arrangedoperating shaft, and a radial carrying arm secured thereto,- and means for manually rotating said shaft.

, 6. In a rheostat, the combination -of 'a shell attached to "said lugs, a longitudinal bar of insulating material secured to said sp der, a ring shaped resistance element,

movable contact member and electrical connections mounted on said bar, the movable contact member comprising a centrally ar-.

ranged. shaft, a radial carrying arm pivoted thereto and a coiled spring intermediate the shaft and arm, and means for manually rotating the shaft.

nections mounted on said bar, the movablecontact member comprising in part a ccntrally arranged operating shaft, and a radial carrying arm secured thereto, and

means for manually rotating said shaft, the same comprising an .actuatifig stem arranged in longitudinal alinement with the operating shaft and provided atone end of May 1912.

with an operating means and at the other end With a sleeve of insulatin material the end of which is longitudinal y slotted for operative engagement with lateral projec tions on the end of the operating shaft.

8. In a rheostatfthe combination of a supporting spider having a plurality of circularly disposed lugs, a reticulated inclosing shell attached to said lugs, a longitudinal bar of insulating material secured to said spider, a ring shaped resistance element, movable contact member and electrical connect-ion's mounted on said bar, a supporting bracket attached to said bar, the resistance element comprisin in part an open hand ring or core the en s of which overlap, and a bolt attaching said ends to the bracket aforesaid. v

Signed at Chicago, Illinois, this 7th day 4 THOMAS RHODUS. Witnessesr 1 ROBERT BURNS, HENRY MOE. 

